Radical polymerizable macrocyclic resin compositions with low polymerization stress

ABSTRACT

A composition of macrocyclic oligomer with at least one (meth)acrylate polymerizable group. A method includes preparing an activated precursor of an oligomer at pseudo high-dilution conditions. A method also includes preparing an activated precursor of an oligomer by reacting the precursor with an activated coupling agent, wherein the precursor is condensable and polymerizable.

RELATED APPLICATIONS

This is a Continuation Application which claims priority to pending U.S.Ser. No. 11/153,090 filed on Jun. 15, 2005 which in turn claims priorityto provisional patent application Ser. No. 60/579,836 (Case LDC-949A)filed on Jun. 15, 2004.

FIELD OF THE INVENTION

This invention relates to free radical polymerizable macrocycliccompounds and composition, which feature by their low shrinkage and lowcontraction stress upon polymerization. Such low shrinkage and lowstress resin could find their wide range of applications, especially inmicroelectronic, special coating and restorative dentistry where thedimensional stability and contraction stress within cured materials arecritical to the total performance.

BACKGROUND OF THE INVENTION

The polymerization shrinkage of curable material is referred to thedimensional contraction during polymerization or curing, because theformation of covalent bonding during polymerization bring the moleculescloser each other than that while they are free in van der Wallsdistance. The origin of polymerization stress, on the other hand, comesfrom a restrained polymerization or shrinking during curing. Therefore,it is not only related to polymerization shrinkage, but also isdependent on the polymerization kinetics.

It is well known that with increasing molecular weight, the mobility ofpolymeric chain would be limited, the diffusion is becoming the ratecontrol factor. In addition, such a limited mobility in a cross-linkingsystem appear to come earlier in comparison with linear system, whichmeans extra reaction would lead to an increasing polymerization stress.There are different ways to control the stress generation anddevelopment:

-   -   1. Slow down the polymerization rate;        -   Introducing a special rate controller like stable radicals;        -   Creating different polymerization zones from which the            stress developed in a polymerized zone could be transferred            to its adjacent unpolymerized zone and got relief like            segmental polymerization technique;        -   Employing different polymerization groups;        -   Using large-size macromonomer to limited its reactivity at            the early stage;    -   2. Reduce the conversion;        -   Pre-building a 2D or 3D structure like macrocyclics,            dendrimers or hyperbranches;    -   3. Limiting the cross-link density to offer acceptable        mechanical property.

To reduce polymerization shrinkage and stress in the specific dentalrestorative composite, all of above approaches are taking into account.In this invention, however, the objective is to present a general methodto produce a macrocyclic oligomer which would be converted into 3Dnetwork via free radical polymerization.

U.S. Pat. No. 4,644,053, disclosed a method to synthesize singlemacrocyclic compounds. Then various macrocyclics oligomers, includingcarbonates, esters, amides, ethers, imides, sulfides, et al, have beenprepared. However, high temperature ring-opening reaction has to beinvolved to convert these macrocyclics into high molecular weightpolymers.

U.S. Pat. No. 5,047,261, disclosed a composition containing afive-member carbonate cyclic group for fast copolymerization withmathacrylate.

U.S. Pat. No. 5,792,821, disclosed polymerizable cyclidextrin (CD)derivatives, in which methacrylate was attached on CD.

U.S. Pat. No. 5,962,703, disclosed functionalized bicyclic methacrylatewith norboneyl or norbonadienl group.

U.S. Pat. No. 6,043,361, disclosed polymerizable cyclic allylic sufidesis used for low shrinkage materials.

APPROACH

The macrocyclic oligomers are prepared under pseudo-high-dilutioncondition via a condensation between a reactive and free radicalpolymerizable precursor and various coupling agents to afford carbonate,ester, siloxane, phosphonate, et al linkages to result in macrocyclicoligomers. To avoid the premature polymerization of methacrylate groups,the condensation groups usually have to be activated to assure a mildreaction for cyclization with the coupling monomers.

BisGMA is one of widely used dental resin and it contains two freeradical polymerizable group, methacrylate and two hydroxyl groups. Thisturns BisGMA an ideal candidate for polymerizable macrocyclic oligomer,although the presence of BisGMA isomer would make more complicated tothis approach. As shown in Scheme I, carbonyldiimidazol (CDI, 1), wasused to selectively reacted with the secondary alcohol in BisGMA (2) togive an activated BisGMA, DIZ-BisGMA(3). It was isolated and thechemical structure of DIZ-BisGMA was fully characterized with FITR andNMR. Actually, according to the recent report by Davis et al ofCourtlaulds, England, CDI and its intermediates could exhibitsurprisingly specificity towards primary, secondary, tertiary functionalgroups, of the same type, during the controlled formation of variouswell-defined molecular sequence. Our idea is to adopt same chemistry ofCDI and to activate the two secondary hydroxyl group. Furthermore, anactivated precursor, DIZ-BisGMA, was made to react with various primarydiols 1,10-decanediol, under a pseudo high-dilution condition, as shownin Scheme II. Both reactants were simultaneously charged into the systemin a high-dilution condition via slowly, precisely controlled additionto ensure a favorable formation of cyclic product. Since the product,C10-CYCBGM (5), is accumulated with a final concentration of 0.02M,which is much higher than the classical high dilution condition(0.001M), this procedure is, therefore, referred as pseudo-high-dilutionapproach. Since imidazol is produced from both precursor and cyclizationsteps, a continuous process was successfully developed without directseparation of DIZ-BisGMA.

1. A dental composition comprising a macrocyclic oligomer with at leastone (meth)acrylate polymerizable group.
 2. A method of preparing adental composition comprising a polymerizable macrocyclic oligomer,comprising the step of preparing an activated precursor of an oligomerat pseudo high-dilution conditions.
 3. A method claimed in 2, whereinsaid activated precursor is liquid, crystalline solid or a combinationof both.
 4. A method as in claim 2, wherein said precursor itself ispolymerizable.
 5. A method as in claim 2, comprising the step ofreacting said precursor with a coupling agent selected from the groupconsisting of primary diols, secondary amines, diacids and combinationsthereof.
 6. A method as in claim 5, wherein said coupling agent isaliphatic, aromatic or both.
 7. A method of preparing a dentalcomposition comprising a polymerizable macrocyclic oligomer, comprisingthe step of preparing an activated precursor of an oligomer by reactingsaid precursor with an activated coupling agent, wherein said precursoris condensable and polymerizable.